In a conventional ink-jet printer, operational tasks are affected by the printer's ambient environment. This makes a determination of the printer's ambient environment an important step in selecting the printer's optimal operational subroutines. Conditions such as temperature and humidity, for example, will affect ink viscosity, and, correspondingly, will impact on the frequency with which printhead servicing should occur. This in turn will impact on the selection of the printer's optimal servicing subroutine, the operational subroutine which determines the frequency with which a printer's printheads are flushed and wiped. The ambient temperature and humidity will also affect factors such as ink drying time and record media absorption characteristics, both of which are important in selecting the printer's optimal printing subroutines. The printing subroutines, it will be appreciated, are operational subroutines which determine variables such as the rate of record media throughput and the economy of ink use.
Based on the foregoing, it should be apparent that the effectiveness of a printer's operational subroutines will change with the environment in which the printer operates, an environment which may be ambiguous at the time the printer's operational subroutines are set. Although known printers have been manufactured to operate under assumed environmental conditions, conditions generally have been assumed at the time of manufacture with little or no information concerning the actual environment in which the printer will be used. This has led to problems in the selection of effective operational subroutines where the printer's environment is not known at the time of manufacture, or where such environment is subject to change. These ambiguities have made it necessary to select operational subroutines which could be used under all environmental conditions in which the printer operates, an arrangement which may lead to the selection of less than optimal operational subroutines. A need has thus arisen for an arrangement whereby a printer's operational subroutines may be selected in view of actual environmental conditions, rather than those which have been assumed. Prior art printers have not met this need.
In the past, the aforementioned problems have been addressed simply by assuming a "worst case" environment when selecting operational subroutines. Servicing subroutines are thus chosen to direct frequent printhead servicing, it being assumed that the printer will operate in a cool/dry environment wherein the printhead nozzle is particularly susceptible to viscous plugs. Printing subroutines similarly are chosen to accommodate use of the printer in an undesirable environment, each subroutine being chosen assuming an environment which is least desirable for performing the corresponding printing task. The printing subroutine which directs the rate of record media throughput, for example, is chosen assuming a "worst case" ink drying time, it being assumed that the printer will operate in a cool/wet environment wherein ink is slow to dry. The printing subroutine which determines the printer's print mode (i.e., the number of printhead passes per line of characters) is chosen to compensate for poor record media absorption characteristics, characteristics common to a cool/dry environment wherein a greater number of printhead passes will be required to produce acceptable text.
Although effective in avoiding printer failure, the aforementioned assumptions may result in the use of less than optimal operational subroutines, particularly where the printer operates under environmental conditions which are different from the "worst case" conditions assumed. This can lead to unnecessary printhead servicing, slower than necessary record media throughput, and a waste of materials such as servicing solvents and ink. These factors in turn may result in increased component wear, increased printer down time, and increased operating cost.